Analysis of the levels of hormone in an individual can provide important and helpful prognostic information. For example, detected hormone levels may enable an evaluation of a woman's health concerns such as fertility, pregnancy and menopause. One component in evaluating a woman's fertility status is assessing her ovulatory function. The average menstrual cycle generally lasts 28 days, during which there is a transition from the follicular phase to the luteal phase. The follicular phase of the menstrual cycle begins on the first day of menstruation and is followed by a rise in follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estrogen, the latter promoting the maturation of a follicle. Once estrogen levels reach an optimal concentration and duration, the pituitary gland is prompted to release a large burst of LH secretion that significantly raises the concentration of circulating LH in blood. This rise in circulating hormone is known as LH surge. This surge in LH marks the transition to the luteal phase of the cycle, resulting in final maturation of the follicle, release of a mature oocyte from the follicle (ovulation), and corpus luteum formation. After ovulation, estrogen levels continue to rise along with an increase in progesterone levels in order to prepare the endometrium for implantation. If fertilization of the oocyte occurs, the implantation of the fertilized oocyte within the uterine endometrial lining triggers production of human chorionic gonadotropins (hCG) that maintains the corpus luteum and progesterone production. However in the absence of fertilization, the corpus luteum deteriorates resulting in a decrease in the levels of both estrogen and progesterone, and sloughing of the endometrial lining thereby marking the onset of the next cycle.
In assessing ovulatory function, daily measurements of LH levels may be used to predict the timing of ovulation. The rise in blood LH may occur ˜24-36 hours prior to ovulation.
Measurements of serum progesterone levels 18 to 24 days after the onset of menses or seven days before the next cycle may be used to confirm whether ovulation had occurred. In the event of a confirmed pregnancy, serum progesterone levels may be utilized to assess nonviable pregnancies, e.g., ectopic pregnancy or spontaneous abortion (miscarriage). In pregnant individuals, a serum progesterone value of ≥25 ng/ml is 98% of the time associated with a viable pregnancy, while a value of <5 ng/ml identifies a nonviable pregnancy.
Another component in evaluating a woman's fertility status may be assessing the functioning potential of the ovary with respect to the quantity and quality of the oocytes within the ovary, commonly referred to as ovarian reserve. An acceleration of follicular loss is prevalent in the last 10-15 years before menopause. This loss correlates with a subtle increase in FSH. One test that may be used to assess ovarian reserve is the Day 3 FSH test. This test determines the level of FSH on cycle day three during which estrogen level is expected to be low. A cycle day three FSH level <10 IU/L is suggestive of adequate ovarian reserve, whereas an FSH level >25 IU/L is associated with a chance of pregnancy close to zero during ovulation induction.
A woman's fertility may also be affected by fluctuations in thyroid gland function. The measurement of thyroid-stimulating hormone (TSH) levels may be used as a screening test. Briefly, thyrotropin-releasing hormone (TRH) prompts the pituitary gland to produce TSH. However, TRH also prompts the pituitary to release more of the hormone prolactin (PRL). Elevations of PRL can interfere with ovulation by suppressing release of the hormones LH and FSH, which stimulate the ovary. Low levels of TSH may also interfere with the rate of metabolism of sex hormones, which may also cause ovulatory disorders. Menstrual irregularities and bleeding problems are common in hypothyroid women.
Diagnostic tests for screening analytes, e.g. urinary hormones or metabolites thereof, may utilize antibodies specific to the analyte. A change in the level from a predetermined threshold level may be noted by differences in color or color intensity compared with the color in a reference window or a reference guide. The color change may be produced using techniques such as enzyme-linked immunosorbent assays or lateral flow color matching assays to indicate the amount of analyte in a urine sample.
Improvements to the diagnostic tests for fertility monitoring have been made by removing the step which required the individual to interpret the results. In these products, electronic sensors and displays provide clear outputs indicating analyte levels. For example, the Clearblue® Easy Fertility Monitor (CBEFM) provides a method for monitoring the fertility status of an individual using two hormones: LH and estrogen with electronic reading and a digital display. The Clearblue® Digital Ovulation Test (CDOT) is another commercially available device, which employs a variable threshold for LH surge determination, and is also an improvement over the color matching visually read tests. Although both CBEFM and CDOT show improvement over the art, there still remains a need for such diagnostic devices that are affordable to the average consumer and provide simplicity of use over the prior art. Accordingly, improvements in detection systems are desirable.